1. Field of the Invention
This invention relates to a tool useful for cleaning out bore holes and tubular conduits, and particularly to the cleanout and stimulation of bore holes in deviated or horizontal subterranean wells.
2. Description of Related Art
The use of jetting nozzles attached to tubing or coiled tubing for cleaning out and removing fill material and debris, often compacted, from bore holes and tubulars is well known. With most of the prior art nozzles, pressurized or pulsating jets of water or other fluids such as chemicals, solvents, acids, nitrogen, or the like, are discharged through a fixed pattern of channels and orifices disposed in nozzles. More recently, Halliburton has introduced its Hydro Jet tool and BJ Services has introduced its Tornado coiled tubing nozzle for use in cleanout operations. Both tools are said to be particularly effective for cleanouts of deviated and horizontal wells.
Both tools are believed to utilize sleeves disposed inside the nozzles to selectively close off jets and open other jets during different phases of a cleanout operation. When the tool is being advanced forwardly through a well bore, the sleeve is pinned in a position where the forwardly and radially directed jets are open. When the tool is to be withdrawn, a heavy ball is first dropped down the tubing to impact the sleeve, shear or dislocate the pin, and shift the sleeve to a second position where the forwardly directed jets are closed and the rearwardly directed back jets are opened. The back jets assist in sweeping away sediment that may have settled around the tubing behind the nozzle during entry into the well bore.
Many times, the cleanout operation can be conducted more effectively and efficiently if one can cycle the tool repeatedly through forwardly and backwardly directed movements. Unfortunately, with the prior art nozzles, there has not been a readily available means for cycling the sleeve back to the position where the forwardly facing jets are open and the back jets are blocked without tripping the tool to remove the ball and re-pin the sleeve. Commercially available nozzles are typically unable to vary the fluid discharge pattern or velocity down hole by contact with an obstruction when moving either in or out of the hole. Accordingly, a jet nozzle is needed that can be cycled through sequences of forward and backward motion without having to manually shift some part of the nozzle or trip the tool to reset an internal sleeve or other such mechanical device.